Isn't the whole "totally stomping the other team with kill-streaks and big scores" entirely about attempting "to ruin others' games?"

I mean, unless you think there are people who enjoy losing gunfights...

No. Actually it's not about ruining their game. It's a game with winners and losers. If your team is getting stomped that badly, they are losing. Eventually, they will improve to the point where they are not getting stomped. Those who want to expend effort to practice will get to be at least decent players.

Those who are lazy and don't wish to improve will do like the OP says because it's all they have left.

It's showing up to class, but not doing the work and expecting to pass. Just like those lovely examples of the "No Child Left Behind Act."

Reroll care packages, especially ones that are VSAT and higher. (Effective in core, too, since you can't get teamkilled)

Block doorways. Most people are afraid to teamkill. If they have a mic, even better.

Use EMP grenades to take out friendly equipment, Guardians and Sentry Guns.

If someone is on a streak, teamkill them. During host migration one time, someone on my team said he was 9-0. When host migration finished, I looked at the scoreboard during the countdown and saw he had 0 confirms. I turned around and he happened to be crouched, aimed in on a doorway. I took the liberty of ending his streak. His reaction wasn't nearly as good as I was hoping it would be.

Reroll care packages, especially ones that are VSAT and higher. (Effective in core, too, since you can't get teamkilled)

Block doorways. Most people are afraid to teamkill. If they have a mic, even better.

Use EMP grenades to take out friendly equipment, Guardians and Sentry Guns.

If someone is on a streak, teamkill them. During host migration one time, someone on my team said he was 9-0. When host migration finished, I looked at the scoreboard during the countdown and saw he had 0 confirms. I turned around and he happened to be crouched, aimed in on a doorway. I took the liberty of ending his streak. His reaction wasn't nearly as good as I was hoping it would be.